Multi-material filament woven cage

ABSTRACT

A bearing cage and a method for manufacturing a cage wherein the cage consists of a plurality of circumferentially spaced radially directed cylindrical or rectangular pockets for receipt of roller elements, each pocket having at least a portion of its walls defined by a wound filament of a first material and the cage being defined by a wound filament of a second material.

United States Patent n9] 51 May 15, 1973 Davis [54] MULTI-MATERIALFILAMENT WOVEN CAGE [75] Inventor: Paul B. Davis, Sinclairville, NY.

[73] Assignee: TRW Inc., Cleveland, Ohio [22] Filed: Apr. 17, 1972 [2]]Appl. No.: 244,535

[52] US. Cl ..308/2l7 [5 1] Int. Cl. ..Fl6c 33/46 [58] Field of Search..308/20l, 217

[56] References Cited UNITED STATES PATENTS 3,472,567 10/1969 Johnson..308/201 Primary Examiner-Charles J. Myhre Assistant ExaminerFrankSusko Attorney- Benjamin H. Sherman, et al.

57 ABSTRAC I 11 Claims, 7 Drawing Figures 1 MULTll-MATERIAL FILAMENTWOVEN CAGE BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to anti-friction bearing assemblies and moreparticularly to a roller element retaining and separating cage for suchassemblies.

2. Prior Art Many anti-friction bearing assemblies incorporating eitherball or roller bearings use an element-separating cage. The cage,normally composed of sheet metal or carved phenolic resins or the likegenerally comprises a ring having an axial width with openings thereindefining pockets for receipt of the anti-friction elements. The cage isinterposed between the inner and outer race rings of the bearingassembly and functions to keep the anti-friction elements from bunchingup within the assembly and from contacting one another. The cage rotatesin the assembly as the anti-friction elements roll.

US. Pat. No. 3,472,567 to John H. Johnson, issued Oct. 14, 1969,illustrates a new type of bearing cage. The cage is formed from acontinuous filament or a plurality of filaments which are wrapped insuch a manner as to define the cage. The filaments are thereafter bondedinto fixed ring and pocket shape.

Such wound bearing cages have numerous advantages over prior art solidand multi-piece cages. Further, with the recent development of differentfilaments including metallic and artificial plastic filaments, the cagecan be made of a wide range of materials. Such materials for individualcages can be selected for desired properties.

However, certain installations emphasize the requirement of materialshaving given properties for defining the cage and particularly thoseparts of the cage subject to contact by the rolling elements. Thesematerials are not always the ideal material for formation of the cagefrom other criteria bases. It would, therefore, be advantageous if amethod were devised whereby a wound cage could be constructed whichwould provide individual pockets constructed of the best material forroller element contact or of the strongest material for pocket shapeddefinition, depending upon the criteria chosen, but which would alsoprovide a cage constructed of the best material for the construction ofthe cage as a whole. Up until now, it has not been possible to produce awoven retainer cage constructed of two materials, each material beingpredominant in different areas of the cage.

SUMMARY This invention provides a solution to the above problems byproviding a woven cage wherein each individual pocket is first definedfrom a first woven material and the cage is thereafter defined from asecond woven material. In the preferred embodiment, this is accomplishedby-creating a plurality of pockets, each individually woven from astrand or strands and thereafter connecting each of the individualpockets by a continuous wind to form the cage.

It is therefore an object of this invention to provide a dual materialwoven anti-friction element retainer cage.

It is another object of this invention to provide a filament wovenretainer cage having individual pockets for receipt of the anti-frictionelements, the pockets each having at least a portion of its wallsdefined by a material different than the cage-defining material.

It is a further object of this invention to provide a method ofmanufacturing a filament-wound bearing retainer cage by first winding afilament individually in a configuration to define individual pocketshaving substantially radial walls and open radial ends and then windinga continuous filament or filaments around said pockets and between aplurality of circumferentially spaced pockets to define a ring ofpockets and thereafter bonding said filaments into fixed ring and pocketshape.

It is a further object of this invention to provide a method ofmanufacturing a filament-wound bearing cage constructed of differingmaterials which comprises the steps of providing a fixture with membersthereon having an outer surface defining a pocket shape for receipt ofan anti-friction element, winding a filament around said member todefine a pocket having a hollow interior, and winding a separate anddifferent material filament around a plurality of the defined pockets,fixing the defined pockets in circumferential spaced relation with openradially inner and outer ends and thereafter bonding the filaments intofixed ring and pocket shape.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantagesof the invention will be readily apparent from the following descriptionof certain preferred embodiments thereof, taken in conjunction with theaccompanying drawings, although variations and modifications may beeffected without departing from the spirit and scope of the novelconcepts of the disclosure, and in which:

FIG. 1 is a perspective view partially in section of an anti-frictionbearing assembly equipped with the cage of this invention;

FIG. 2 is a plan view partially in section of a fixture which can beused to form the detainer cage of this invention;

FIG. 3 is a plan view as indicated by the lines llI-IlI of FIG. 2,illustrating a portion of the fixture as wrapped with a first filament;

FIG. 4 is a diagrammatic view illustrating a method of wrapping a secondfilament around pockets formed by the first filament;

FIG. 5 is a fragmentary diagrammatic sectional view of a portion of acompleted retainer cage according to this invention;

FIG. 6 is a cross-sectional diagrammatic view of a retainer cageconstructed according to the teachings of this invention; and

FIG. 7 is a fragmentary cross-sectional view taken along thecircumference on a radial cut of a cage constructed according to theteachings of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings illustrate a cageand method of constructing the cage wherein the cage is designed toreceive and separate roller bearings. It is, however, to be understoodthat a cage with circular pockets can be constructed to receive ballbearings, and that further, the cage could be tapered to receive taperedroller bearings if desired. The method of this invention incorporatesprinciples first taught in U. S. Pat. No. 3,472,567, issued Oct. 14,1969 to John H. Johnson,

and the teachings of that patent are herein specifically incorporated byreference, including the teachings of possible filament materials andbinders such as resins and the like.

FIG. 1 is a perspective view of an anti-friction bearing assemblycomposed of inner 11 and outer 12 race rings, each of which has racewaysl3 and 14 therein. Rollers 15 are received between the race rings in thegrooves 13 and 14 to provide relative rotatability to the rings. A cagestructure 16 is also received intermediate the race rings 11 and 12. Thecage structure 16 comprises a ring of circumferentially spaced pockets,each pocket receiving a roller 15. The function of the cage is toequally space the rolling elements around the race rings and to preventthe elements from rubbing against each other. In this, the cage acts asa separator. Further, in some embodiments, the cage may have a contourto the inner walls of the pockets to retain the rolling elements fromdrop-out in either a radially inwardly, a radially outwardly, or bothdirections. In such instances, the cage is generally described as aretainer. This invention is directed both to separator andseparator-retainer cages.

The cage 16 consists of a pluality of circumferentially spaced pocketportions 18 interconnected by crossover portions 19. The pocket portionsare illustrated as being rectangular in pocket-defined shape for thereceipt of roller bearings. However, cylindrical or other haped pocketsmay be provided to confine other types of anti-friction elements.

In accordance with prior-known teachings, the cage is constructed of awound filament which is wound a plurality of times circumferentiallyaround the cage area to provide a plurality of superimposed filamentswhich are thereafter bound together by a bonding technique. It is to beunderstood that the filament may be a mono-filament or a strandedfilament and the bonding technique may include fusion of the filamentmaterial itself, fusion of bonding materials, cement, thermal orcatalyst set bonding materials or, in general, any type of bond, whichwill lock the strands together into fixed shape. Bonding agents ormethods which allow a degree of flexibility to the resultant cage aredesirable.

The central idea of this invention is best illustrated in FIGS. 5, 6 and7, wherein it is shown that the cage 16 consists of a plurality ofcircumferentially spaced pockets 18 first defined by a wound filament ofa first material 20, the cage being defined by a wound filament of asecond material 21.

As illustrated, the first material 20 is wound circumferentially to formthe individual pockets 18, leaving open the inner and outer diameters ofthe pockets. Thus, the first material 20 comprises a band having aninner shape 23 in conformity with the shape of the pocket (rectangularas illustrated for roller bearings). The bands 24 have a radial heightless than the height of the finished cage whereby the filament of thesecond material 21 overlies the radially inner and outer ends 25 of thebands 24 with an outer cage portion 26.

The second material 21 therefore finishes the definition of theindividual pockets 18 and forms the crossover portions 19 which connectthe individual pockets 18 into a ring configuation. As isdiagrammatically illustrated by the reduced thickness portions 30, thecross-over sections interconnecting the individual pockets are generallyof a dimension less than the outer dimensions of the pocket areas. Thespecific dimensions of the crossover portions difier with the method ofwinding the ring as hereinafter described.

The differences in material between the first material filament and thesecond material filament 21 can vary according to the criteria chosen inselecting the material. As a specific example, where it is desirable toline the pockets with a minimum friction material while retaining a moreflexible and higher-strength material for the formation of the cageitself, the first material bands 24 may be constructed of a graphitefilament while the cage itself may be formed of a fibrous glassfilament. In such a situation, the binding materials for the filamentsmay include polyester resins, epoxy resins, silicon resins, polymersetc. Where the filament material takes the form of a metal wire, thewound strand can be fused together at induction-produced elevatedtemperatures. Additionally, metal and ceramic spring techniques may beused to bond the filaments. A feature of this invention allows the useof different bonding techniques for the different first and secondmaterials. Therefore, the bonding agent or technique used for the bands24 may be chosen on the basis of criteria different from the bondingagent or technique chosen for the bonding of the second material. Thus,for example, where high heat and friction loss resistance is importantin the immediate pocket defining area, the first material could bebonded together by a bonding agent chosen for high heat resistance suchas, for example, a polyimide resin. Thereafter, the second materialcould be bonded together by a material chosen for high strength at lowertemperatures such as by way of example, an epoxy resin.

Other reasons for a choice of differing materials also exist and acatalog of all possible reasons and choices is not possible. As afurther example, where it is desired that the pockets have an absolutefixed shape in a flexible cage, the pockets themselves could be formedof a fused metal filament such as, by way of example, stainless steelbonded by heat fusion and the cage could be constructed of a moreflexible material such as by way of example, nylon filament bonded witha resin binder. Thus, the structural rigidity of the fused metalfilament will result in a shape defined pocket while the flexibility ofthe nylon or like material will result in a flexible cage of rigidpockets.

FIGS. 2, 3 and 4 illustrate a fixture 40 and a method of manufacture ofthe above-described cage. The fixture 40 has a circular disk 41 with aplurality of equally spaced radial holes 42 around the peripherythereof. Winding heads 43 have cylindrical stems 45 received in theholes 42 in snug but movable relation. Each head 43 has a rectangularperiphery 44 sized to form the pocket 18 for the cage 16. In producing acage for ball bearings, the periphery 44 would be circular orcylindrical. In producing retainer cages, the periphery 44 would betapered, having a reduced radially inner section or a reduced radiallyouter section or an arcuate curve with both reduced inner and outersections. In the latter instance, the heads may be constructed in anexpandable manner whereby they can be contracted to release theindividual pockets.

The individual pockets are formed first by a wrapping of the firstmaterial as illustrated in FIG. 3, wherein the individual strands 46 ofthe first material are wrapped around the periphery 44 of eachindividual head 43. A separate strand may be used for each head, or acontinuous wrapping technique wherein each head is wrapped a pluralityof times to build up the band and" then the filament is passed to thenext head to wrap it a plurality of times to build up a second hand maybe used. In any event, each head is wrapped with the first material aplurality of times to build up a band having the desired depth andheight.

Thereafter, the resultant bands may be subjected to a bonding operation,either by setting of the binding agent or by subjecting the strands, ifmetallic, to a fusion process. Alternatively, the individual bands canbe set at a later time in a common treatment with the setting of thesecond material.

As illustrated by FIG. 4, the second material is then wound around theindividual pocket bands to form the ring. Numerous methods of windingillustrated, both fixture winding on the fixture of FIG. 2 and in situwinding, are disclosed in the aforementioned US. Pat. No. 3,472,567, andcan be used in this invention. FIG. 4 illustrates one method whereinfour pockets A through D are illustrated. Two strands 50 and 51 offilament are passed entirely around each pocket and then crossed over tothe next pocket, beginning the wrapping of that pocket on the oppositeside. Thus, the filament 50 begins on the top side of pocket A and iswrapped entirely around the pocket, terminating on the top side. Thefilament 50 then passes to the bottom side of the pocket B, wrapsentirely around pocket B and then passes to the top of pocket C, etc.Filament 51 is illustrated beginning at the bottom of pocket A, passingentirely therearound and then crossing over to the top of pocket B, etc.If it is considered that pocket D represents schematically the start ofanother pass through pockets A, B and C, whereby pocket D will be yetanother view of pocket A, then filaments 50 and 51 can be considered asbeing a single filament, with the filament terminating on the same side,i.e., top or bottom as viewed in FIG. 4, of pocket C as it begins onpocket A. Therefore, when it gets to pocket A the second time around asillustrated by D, it would begin at the opposed side of that pocket.Thus, for example, if pocket D is considered a repeat of pocket A, thenfilament 50 would begin pocket A at the line indicated as 51 immediatelyto the left of pocket A. Thus, for an odd number of pockets, the lineson repeated passes would be the same for a single filament as areillustrated for dual filaments on a single pass for even numbers ofpockets. Windings such as those illustrated which pass the filamententirely around the pocket before proceeding to the next pocket willresult in a substantially thicker walled pocket than the crossoverpoint, resulting in a cage resembling that illustrated in FIG. 1.Windings which do not pass entirely around a pocket before crossing tothe next pocket, but rather sinuously wrap the pockets, will result in aheavier crossover portion. It is preferred that the windings passingfrom one pocket to the other always cross over to a different side.Thus, for example, as illustrated, windings which terminate on the topas viewed in FIG. 4 of one pocket will pass over to the bottom of thenext pocket. Further, in order to reduce the radial thickness of thecrossover portion, a winding which terminates at the circumferentiallyouter portions of one pocket should cross over to the circumferentiallyinner portions of the next pocket, and vice-versa. This results in aradially smaller crossover portion. Smaller or thinner crossoverportions assure that the crossover portion of the cage will neverinterfere with the operation of the assembly by contacting either of therace rings.

After wrapping the second material to form the cage, the cage issubjected to a bonding operation to fix the cage in fixed ring andpocket shape.

It can therefore be seen from the above that my invention provides for afilament wound bearing cage constructed of two separate filamentmaterials, one of which is used to line the individual pockets and theother of which is used to form the cage into ring shape. Also shown anddescribed are method of forming the cage.

Although the teachings of my invention have herein been discussed withreference to specific theories and embodiments and although illustrativemeans for accomplishing explained results have been described, it is tobe understood that these are by way of illustration only and that othersmay wish to utilize my invention in different designs or applications.

I 'claim as my invention:

ll. In a filament wound bearing cage having a plurality ofcircumferentially spaced anti-friction element receiving pockets withradially inner and outer open ends and radially continuous wallsdefining the pockets with a plurality of superimposed filaments wound todefine the pockets and crossover portions between the pockets connectingadjacent pockets to one another in fixed ring shape, the improvement of:a first filament material defining a portion of the pocket walls aroundthe inner periphery of the pocket, and a second different filamentmaterial interconnecting the pockets and forming the pockets into fixedring and pocket shape.

2. The method of making a bearing cage composed of a ring ofcircumferentially spaced closed annular pockets, each with radiallyspaced open inner and outer peripheral ends connected by a continuousradial wall and connecting portions between the pockets holding thepockets in ring-defining relation which comprises: winding 21 firstmaterial filament a plurality of times in a manner to provide a plualityof superimposed filament portions defining each individual pocket,winding a second material filament a plurality of times to providesuperimposed filament portions connecting the pockets formed by thefirst filament material portion together in circumferentiallyspacedapart ring formation, the second different material filamentforming the connecting portions and bonding the superimposed filamentportions together into fixed ring and pocket shape.

3. The method of claim 2 wherein the first material filament is wound toprovide a portion of the walls of each pocket in the manner of a bandwhose inner surface defines the pocket, and the second filament is woundto encompass the outer surface of said bands and to connect the bandscircumferentially together in spaced-apart relation.

4. The method of claim 3 wherein the second material filament is woundto also provide a portion of each pockets defining wall radially beyondthe bands formed by the winding of the first material filament.

5. A filament wound bearing cage having a plurality of circumferentiallyspaced-apart roller element receiving pockets defined by wound filamentportions and connecting portions circumferentially between the pocketsconnecting the defined pockets to one another in a ring shape, a portionof each pocket defined by a first filament wound to provide a bandaround the pocket, the band having open radially inner and outer endsand a continuous radial wall intermediate the ends, the radial walldefining a portion of the pocket on its inner surface, the bands beingreceived in a ring defined by a second different material filament woundaround each of the bands and between each adjacent band into a woundring of circumferentially spaced pockets, the filaments being bondedtogether into fixed ring and pocket shape.

6. The apparatus of claim wherein each of the bands has a height and athickness greater than the individual filament.

7. The apparatus of claim 6 wherein each of the bands iscircumferentially spaced from an adjacent band by a connecting portioncomposed of a plurality of windings of the second material filament.

8. The apparatus of claim 7 wherein the second material filamentoverlies the radial ends of the bands and has a portion defining aportion of each individual pocket radially beyond the ends of the bands.

9. An anti-friction element cage for bearings comprising: a ring ofcircumferentially spaced closed annular pockets with radially spacedinner and outer peripheral ends and a continuous radial wall extendingbetween said ends and portions between the pockets joining the pocketsinto the ring, a cage being formed of a flexible filament wound toprovide a plurality of superimposed filament portions forming theportions between the pockets, and each of the pockets having a bandtherearound with an inner surface defining a pop tion of the pocket, theband composed of a pluality of windings of a second different materialfilament, and the filaments bound together in fixed ring and pocketshape.

10. An anti-friction element receiving cage for bearings comprising acage member having a plurality of circumferentially spaced-apart pocketsfor receipt of the roller elements, each of said pockets having cavitydefining walls with open radially inner and outer ends, each of saidpockets having at least a portion of said walls defined by filamentwound a plurality of times therearound providing an inner surfacedefining a portion of said walls, the filament windings being bondedtogether and the filament being a material different than the remainderof the cage.

11. A method of manufacturing a filament-wound bearing cage constructedof differing materials which comprises the steps of providing a fixturewith members thereon having an outer surface defining a pocket shape forreceipt of an anti-friction element, winding a filament around saidmember to define a pocket having a hollow interior, and winding aseparate and different material filament around a plurality of thedefined pockets, fixing the defined pockets in circumferential spacedrelation and with open radially inner and outer ends and thereafterbonding the filaments into fixed ring and pocket shape.

1. In a filament wound bearing cage having a plurality ofcircumferentially spaced anti-friction element receiving pockets withradially inner and outer open ends and radially continuous wallsdefining the pockets with a plurality of superimposed filaments wound todefine the pockets and crossover portions between the pockets connectingadjacent pockets to one another in fixed ring shape, the improvement of:a first filament material defining a portion of the pocket walls aroundthe inner periphery of the pocket, and a second different filamentmaterial interconnecting the pockets and forming the pockets into fixedring and pocket shape.
 2. The method of making a bearing cage composedof a ring of circumferentially spaced closed annular pockets, each withradially spaced open inner and outer peripheral ends connected by acontinuous radial wall and connecting portions between the pocketsholding the pockets in ring-defining relation which comprises: winding afirst material filament a plurality of times in a manner to provide apluality of superimposed filament portions defining each individualpocket, winding a second material filament a plurality of times toprovide superimposed filament portions connecting the pockets formed bythe first filament Material portion together in circumferentiallyspaced-apart ring formation, the second different material filamentforming the connecting portions and bonding the superimposed filamentportions together into fixed ring and pocket shape.
 3. The method ofclaim 2 wherein the first material filament is wound to provide aportion of the walls of each pocket in the manner of a band whose innersurface defines the pocket, and the second filament is wound toencompass the outer surface of said bands and to connect the bandscircumferentially together in spaced-apart relation.
 4. The method ofclaim 3 wherein the second material filament is wound to also provide aportion of each pocket''s defining wall radially beyond the bands formedby the winding of the first material filament.
 5. A filament woundbearing cage having a plurality of circumferentially spaced-apart rollerelement receiving pockets defined by wound filament portions andconnecting portions circumferentially between the pockets connecting thedefined pockets to one another in a ring shape, a portion of each pocketdefined by a first filament wound to provide a band around the pocket,the band having open radially inner and outer ends and a continuousradial wall intermediate the ends, the radial wall defining a portion ofthe pocket on its inner surface, the bands being received in a ringdefined by a second different material filament wound around each of thebands and between each adjacent band into a wound ring ofcircumferentially spaced pockets, the filaments being bonded togetherinto fixed ring and pocket shape.
 6. The apparatus of claim 5 whereineach of the bands has a height and a thickness greater than theindividual filament.
 7. The apparatus of claim 6 wherein each of thebands is circumferentially spaced from an adjacent band by a connectingportion composed of a plurality of windings of the second materialfilament.
 8. The apparatus of claim 7 wherein the second materialfilament overlies the radial ends of the bands and has a portiondefining a portion of each individual pocket radially beyond the ends ofthe bands.
 9. An anti-friction element cage for bearings comprising: aring of circumferentially spaced closed annular pockets with radiallyspaced inner and outer peripheral ends and a continuous radial wallextending between said ends and portions between the pockets joining thepockets into the ring, a cage being formed of a flexible filament woundto provide a plurality of superimposed filament portions forming theportions between the pockets, and each of the pockets having a bandtherearound with an inner surface defining a portion of the pocket, theband composed of a pluality of windings of a second different materialfilament, and the filaments bound together in fixed ring and pocketshape.
 10. An anti-friction element receiving cage for bearingscomprising a cage member having a plurality of circumferentiallyspaced-apart pockets for receipt of the roller elements, each of saidpockets having cavity defining walls with open radially inner and outerends, each of said pockets having at least a portion of said wallsdefined by filament wound a plurality of times therearound providing aninner surface defining a portion of said walls, the filament windingsbeing bonded together and the filament being a material different thanthe remainder of the cage.
 11. A method of manufacturing afilament-wound bearing cage constructed of differing materials whichcomprises the steps of providing a fixture with members thereon havingan outer surface defining a pocket shape for receipt of an anti-frictionelement, winding a filament around said member to define a pocket havinga hollow interior, and winding a separate and different materialfilament around a plurality of the defined pockets, fixing the definedpockets in circumferential spaced relation and with open radially innerand outer ends and thereafter bonding the filaments into fixed ring andpocket shape.